#include<vector>
#include<string>
using namespace std;
class Solution
{
public:
    int minimumDeleteSum(string s1, string s2)
    {
        int m = s1.size(), n = s2.size();
        vector<vector<long long>> dp(m + 1, vector<long long>(n + 1, 0));
        s1 = ' ' + s1, s2 = ' ' + s2;
        for (int i = 1; i <= m; i++)
        {
            dp[i][0] = dp[i - 1][0] + s1[i];
        }
        for (int j = 1; j <= n; j++)
        {
            dp[0][j] = dp[0][j - 1] + s2[j];
        }
        for (int i = 1; i <= m; i++)
        {
            for (int j = 1; j <= n; j++)
            {
                dp[i][j] = (s1[i] == s2[j] ? dp[i - 1][j - 1] : min(dp[i - 1][j] + s1[i], dp[i][j - 1] + s2[j]));
            }
        }
        return dp[m][n];
    }
};